The broad objective of this request is to establish a Center for Clinical Research specializing in periodontal diseases. A group of clinical periodontists and basic scientists have been assembled at SUNYAB to study key microbiological and host response factors important in periodontal diseases. In addition studies of periodontal therapy and prevention of periodontal disease are proposed. New approaches to microbial diagnosis of periodontal diseases using immunofluorescent tests for specific pathogenic bacteria, and exoenzyme production will be studied. Host response factors such as lymphocyte and neutrophil function tests, complement activation patterns in gingival fluid and antibody levels will also be evaluated to better understand the role of these factors in periodontal disease. These host response factors may also provide diagnostic and prognostic aids. Determination of host factors defective in periodontal disease (such as the neutrophil defects seen in periodontosis) also will be studied as a basis for modification of these factors as an aid in therapy.